The overall objective of this protocol is to isolate and characterize baboon embryonic stem (ES) cells for the purpose of providing a model of early cell growth and proliferation similar to that in humans, and as a source of differentiation-driven cells, tissues, and organs. Baboons are used as a model of bone marrow transplantation, and an ES cell line will be a useful source of blood cell precursors, thus helping to conserve the number of animals for biomedical research. Breeding females are monitored closely and embryos are collected nonsurgically at 7-8 days post-ovulation. In the last few months of 1998, 4 embryos and 3 unfertilized eggs were collected. Two embryos were sent to the Wisconsin RPRC for cell derivation, but no ES cells were derived. Primary progress in 1998 was in the area of protocol and technique. Baboons are now housed in compounds instead of individual cages, providing them with more space and environmental enrichment. Sedation protocols have prov en to be effective for the procedure and have not shown any adverse effects on health. The procedure for flushing embryos from the uterus takes less than 20 minutes and ultrasound confirmation is now unnecessary. WaRPRC employees designed a new cannula set that facilitates rapid and non-traumatic entry into the uterus. The embryos are no longer being shipped to the Wisconsin RPRC for embryonic stem cell derivation. Dr. James Thomson has provided all of the necessary chemicals and antibodies for the derivation of the ES cells at the University of Washington in collaboration with the Department of Comparative Medicine. FUNDING NIH grant RR00166 and departmental funds at the University of Washington.